Markiplier's Letters To Jack

After the famous Youtuber Markiplier dies (or so it seemed), a strange box of letters are discovered. These letters are from all of Jack's friends, mostly from Mark. They are addressed to Jack. In the letters, secrets are discovered, causing questions to form. Was Mark really dead? Or was Jack's reality not what it seems? What is really going on?
**WARNING: THIS STORY MAY BE SAD TO SOME PEOPLE, SO IF YOU'RE SENSITIVE TO THIS KIND OF STUFF.... PLEASE DON'T READ IT THEN.**